Hydraulic cylinder apparatus

ABSTRACT

A feed drawer cylinder assembly for a concrete block molding machine. The assembly is constructed and arranged in association with the hydraulic circuit for the agitator motor of the machine to open a circuit to the motor in timed relation to movement of the cylinder piston to a discharge position of the feed drawer. The cylinder assembly is also constructed to provide improved deceleration characteristics of the piston at each end of its stroke during normal cushioning of the piston in the cylinder.

o J 6 E1116 tates ten 1 1 ,655,315 Bopp [4 1 Apr. 11, 1972 [54] HYDRAULIC CYLINDER APPARATUS 2,396,787 3/1946 Hawthorne ..91/402 x 2,976,844 3/1961 Goldring ..91/26 X [72] Invent 3,239,907 3/1966 Harshberger ..25/41 R [73] Assignee: Go Corp. Inc., Adrian, Mich.

Primary Examiner-J. Spencer Overholser [22] Flled' 1970 Assistant Examiner-Ben D. Tobor [21] App]. No.: 7,570 Att0rneyOlsen and Stephenson 52 US. Cl ..425/145, 91/26, 91/394, [57] ABSTRACT 91/402, 425/200 425/449 A feed drawer cylinder assembly for a concrete block molding 1 ..B28b machine The assembly is Constructed and arranged in as l l held of Search "25/41 41 R; 91/105 sociation with the hydraulic circuit for the agitator motor of 91/394 3961 402 the machine to open a circuit to the motor in timed relation to movement of the cylinder piston to a discharge position of the l 5 6] References cued feed drawer. The cylinder assembly is also constructed to pro- UNITED STATES PATENTS vide improved deceleration characteristics of the piston at each end of its stroke during normal cushioning of the plston 3,10 DaVlS X in the cylinder 3,247,767 4/1966 Aslan ..91/26 3,502,002 3/1970 Whiteman ..91/402 X 7 Claims, 1 Drawing Figure 1 i 54 MOLD 1 5091 I L J PATENTEDAPR 1 1 m2 INVENTOR CECIL W. BOPP \J wan 7; ATTORNEYS BACKGROUND OF THE INVENTION The present invention relates to improvements in hydraulic cylinder assemblies and associated hydraulic circuits adapted primarily, but not exclusively, for use in concrete block making machinery.

It is conventional practice to provide one or two hydraulic cylinder assemblies for moving a feed drawer of a concrete block molding machine between a concrete charging hopper and a mold box, as is shown for example in US. Letters Pat. No. 3,107,410, issued Oct. 22, 1963 to Robert 0. Davis. In apparatus of this type, it is also common practice to provide a hydraulically driven agitator motor or similar apparatus for vibrating or agitating the mold box and its contents when the concrete from the feed drawer has been discharged into the mold box.

There is a constant need in this field to provide improvements which will shorten cycle time of the block making machine; which will reduce valving so as to reduce initial costs as well as maintenance costs of the machine; which will eliminate inertia problems that arise from constant moving of heavy masses, such as feed drawers of concrete, and the like.

SUMMARY OF THE INVENTION The present invention has overcome some of the shortcomings of the prior art and has provided an improved feed drawer hydraulic cylinder and related circuit for use in a concrete block making machine. The improvements are not limited for use with concrete block making machinery but can also be used in other suitable applications.

According to one form of the present invention apparatus is provided for use in a concrete block making machine including the combination of supply means for supplying hydraulic fluid under pressure, agitator means responsive to hydraulic fluid under pressure for agitating concrete in the mold box of the machine, and a feed drawer cylinder assembly operably connected to the feed drawer and in communication with the supply means for moving the feed drawer from a receiving position at the feed hopper of the machine to a discharge position at the mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ingress and egress of hydraulic fluid, a piston slidable to a position at one end thereof whereby said feed drawer is moved to its discharge position, and an additional discharge port in the cylinder adjacent to but spaced from said one end of the cylinder so that the discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover when the latter is moved to said one end of the cylinder, and passage means providing communication between said discharge port and said agitator means so that said agitator means will be actuated in timed relation to movement of said piston to one end of the cylinder. By virtue of this arrangement valving normally provided for starting and stopping the agitator motor can be eliminated and time delays resulting from use of such valving can be avoided thereby providing improved cycle time.

The additional discharge ports can also be used at both ends of the hydraulic cylinder assembly with or without connection to the circuit containing the agitator motor. When so used, improved conditions are provided at the terminal ends of the piston stroke reducing the inertia forces that otherwise would require extra shock absorbers on the block making machine. These results are realized because the high pressure acting on the piston is released during the cushioning of the piston at the ends of the strokes.

Thus, it is among the objects of the present invention to provide improvements in hydraulic cylinder assemblies and associated hydraulic circuits primarily but not exclusively adapted for use with concrete block making machinery.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a longitudinal section through a cylinder assembly embodying the invention, showing fragments of the feed drawer and a concrete block making machine on which the cylinder is anchored, and also showing schematically a portion of the hydraulic circuit which also embodies the present invention and which is part of the block making machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring now to the drawing, the present invention will be described in greater detail. A feed drawer cylinder assembly 10 is shown connected in a portion of the hydraulic circuit 12 of a concrete block making machine, which may be of the type disclosed in the aforesaid U.S. Letters Pat. No. 3,107,410 The circuit includes a motor 14 for driving the hydraulic pump 16 has its suction side in communication with a source 18 of hydraulic fluid and which has its discharge or pressure side connected to the valve 20. The latter is responsive to appropriate signals from the block machine for directing the fluid under pressure, as required, to the opposite ends of cylinder assembly 10 via conduits 22 or 24. In the conventional manner, when one of conduits 22 and 24 is supplying fluid under pressure to one end of cylinder assembly 10, the other conduit will be returning hydraulic fluid from the other end of cylinder assembly 10 to the original source 18.

The cylinder assembly 10 includes a cylinder 26 which has heads 28 and 30 at its ends providing ports 32 and 34 for ingress and egress of the hydraulic fluid in the circuit 12. A piston 36 is slidable in cylinder 26 to a first position shown in solid lines at one end thereof and to a second position shown in broken lines at the opposite end thereof. The piston 36 is connected to the piston rod 38 which extends through the head 28 and is suitably connected to the feed drawer 40, only a portion of which is shown. The other head 30 is anchored in a relatively stationary position by the pin 41 which is fixed to a portion of the block making machine or other structure that is retained in a stationary position relative to the feed drawer 40.

In the illustrated embodiment, the feed drawer 40 will be in its receiving position at the feed hopper (not shown) of the block making machine when the piston 36 is in its first or solid line position and will be in its discharge position at the mold box 43 of the block making machine when the piston 36 is in its second or broken line position. Thus, by appropriately controlling action of the valve 20, the feed drawer 40 can be reciprocated back and forth between its receiving and discharge positions in timed relation to the remainder of the block making machine.

In order to cushion the piston at the opposite ends of the cylinder 26, cushion means are defined between each end of the piston 36 and the adjacent head 28 and 30. For this purpose cushion collars 42 and 44 are mounted on opposite ends of piston 36, and bores 46 and 48 which provide communication between the ports 32 and 34 and the interior of cylinder 26, are of a dimension to receive the collars 42 and 44 for closing such communication. Under these circumstances when the piston 36 is advancing toward one of the heads 28 or 30, the appropriate collar 42 or 44 will initially enter the corresponding bore 46 or 48 capturing hydraulic fluid in the annular cavity defined between the piston 36 and the adjacent end of the cylinder 26. Such captured fluid is then metered to the corresponding port 32 or 34 by the metering passageway 50 or 52 at a controlled rate determined by the cushion screw 54 or 56.

One of the significant features of the present invention is the improvements in the cylinder assembly whereby the momentum of the piston 36, the rod 38 and the feed drawer 40 and its contents, or such other apparatus that may be connected to rod 38, are more effectively reduced or dissipated near the termination of the piston stroke. Normally, when heavy work loads are transmitted through the cylinder assembly l0, shock absorbers must be used to help dissipate the applied loads at the ends of the cylinder strokes. The present invention has reduced the need for such accessory equipment.

In the present invention, the cylinder 26 is provided with additional discharge ports 58 and 60, spaced axially from the ends of the cylinder 26 so that a discharge port 58 or 60 is opened to the high pressure side of the piston by passage of the piston 36 thereover immediately prior to the piston reaching the corresponding end of the cylinder. Each of the additional discharge ports 58 and 60 is in communication with its associated port 32 and 34; port 58 discharging to the port 32 via a passageway 61 including the conduit 62, variable flow control unit 64, agitator motor 66, conduit 68 and valve 70; and discharge port 60 discharging to the port 34 via the passageway 72 which includes the valve 74.

Thus, immediately after the cushioning action starts near the termination of the stroke of the piston 36 in both directions of travel, the pressure acting on the piston 36 is reduced. This has the very desirable effect of reducing the shock that otherwise would be imparted to the supporting structure for the cylinder assembly.

Another significant feature of the present invention is the arrangement whereby the pressurized hydraulic fluid that is utilized to move the piston 36 to its second position, and thereby the feed drawer 40 to its discharge position, is utilized immediately upon discharge through port 58 to drive the conventional agitator motor 66 for agitating the concrete that has been discharged into the mold box of the concrete making machine. This arrangement avoids the time delay that normally will occur if separate valves must be actuated to transmit hydraulic fluid under pressure to the agitator motor when the piston 36 has reached its second position. The arrangement also reduces the cost of valving that must be used and serviced in operation of the machine.

The present invention is not limited to use of the cylinder assembly 10 with a circuit including an agitator motor 66, but can be used in such a circuit which requires other apparatus to be driven in timed relation to the piston reaching a fixed position near the termination of one of its strokes. Also, the pressure release arrangement near the termination of one or both strokes of the piston can also be utilized independently of a circuit such as that including the agitator motor 66. In all such applications, the valves 70 and 74 can be opened to any desired extent in accordance with the setting of the valve stops 76 and 78 which serve to determine the extent of opening of valve apertures 80. Also, as is to be understood, valve 70 will be closed at all times when the piston 36 moves toward its solid line position and valve 74 will be closed at all times when piston 36 moves toward its broken line position, because in both instances the effective area of the valve 70 or 74 facing its port 32 or 34 and exposed to high pressure fluid therein is greater than its effective area facing the passageway communicating with the interior of cylinder 26, and additionally is benefitted by the spring action of the compression springs 82.

it is claimed:

1. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box, the combination of supply means for supplying hydraulic fluid under pressure, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer between a receiving position at said feed hopper and a discharge position at said mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to first and second position at opposite ends thereof and having a piston rod extending through one of said heads for movement of the feed drawer between its receiving and discharge positions in response to movement of the piston between its end positions, additional discharge ports in said cylinder spaced axially from the ends of said cylinder so that a discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover immediately prior to the piston reaching the corresponding end of the cylinder, passageways provided at each end of the cylinder placing each additional discharge port in communication with the associated main port at its end of the cylinder, each passageway containing means to prevent return flow from the passageway to the cylinder, and an agitator motor in series with one of said passageways, said motor actuated when the piston moves to one of its end positions thus opening one of said additional ports.

2. The combination that is defined in claim 1, wherein hydraulic cushion means are defined between each end of the piston and the adjacent head of the cylinder, each said cushion means including a cavity provided between the piston and the adjacent head in which fluid is captured near the termination of the piston stroke and metered to the main port and said additional discharge port at each end is spaced from its associated head a distance such that fluid has been captured in said cavity prior to the piston uncovering said discharge port, whereby hydraulic fluid pressure acting on the piston will be reduced during the cushioning of the piston.

3. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box and agitator means for agitating the concrete discharged into the mold box, the combination of supply means for supplying hydraulic fluid under pressure, agitator means responsive to hydraulic fluid under pressure for agitating concrete in a mold box, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer from a receiving position at the feed hopper to a discharge position at the mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to a position at one end thereof whereby said feed drawer is moved to its discharge position, and an additional discharge port in said cylinder adjacent to but spaced from said one end of said cylinder so that the discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover when the latter is moved to said one end of the cylinder, and passage means providing communication between said discharge port and said agitator means so said agitator means will be actuated in timed relation to movement of said piston to said one end of the cylinder.

4. The combination that is defined in claim 3, wherein hydraulic cushioning means are defined between each end of the piston and the adjacent head of the cylinder, each said cushioning means including a cavity provided between the piston and the adjacent head in which fluid is captured near the termination of the piston stroke and metered to the main port, and said additional discharge port is spaced from its associated head a distance such that fluid is captured in said cavity prior to the piston uncovering said discharge port, whereby hydraulic fluid pressure acting on the piston will be reduced during the cushioning of the piston at said one end.

5. The combination that is defined in claim 3, wherein variable flow control means are located in said passage means for controlling operation of said agitator means,

6. The combination that is defined in claim 4, wherein a similar additional discharge port is in said cylinder adjacent to but spaced from the other end of the cylinder, and passage means provide communication between said similar port and the port in its associated head.

7. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box,

the combination of supply means for supplying hydraulic fluid under pressure, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer between a receiving position at said feed hopper and a discharge position at said mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to first and second position at opposite ends thereof and having a piston rod extending through one of said heads for movement of the feed drawer between its receiving and discharge positions in response to movement of the piston between its end positions, an additional discharge port in said cylinder spaced axially from one end of said cylinder so that a discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover immediately prior to the piston reaching the corresponding end of the cylinder, hydraulic motor means for actuation of apparatus associated with the concrete block forming operation, and a passageway in communication with said additional discharge port and said hydraulic motor means for supplying high pressure hydraulic fluid to said hydraulic motor means so that the motor means can actuate said apparatus in timed relation to the location of said piston. 

1. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box, the combination of supply means for supplying hydraulic fluid under pressure, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer between a receiving position at said feed hopper and a discharge position at said mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to first and second position at opposite ends thereof and having a piston rod extending through one of said heads for movement of the feed drawer between its receiving and discharge positions in response to movement of the piston between its end positions, additional discharge ports in said cylinder spaced axially from the ends of said cylinder so that a discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover immediately prior to the piston reaching the corresponding end of the cylinder, passageways provided at each end of the cylinder placing each additional discharge port in communication with the associated main port at its end of the cylinder, each passageway containing means to prevent return flow from the passageway to the cylinder, and an agitator motor in series with one of said passageways, said motor actuated when the piston moves to one of its end positions thus opening one of said additional ports.
 2. The combination that is defined in claim 1, wherein hydraulic cushion means are defined between each end of the piston and the adjacent head of the cylinder, each said cushion means including a cavity provided between the piston and the adjacent head in which fluid is captured near the termination of the piston stroke and metered to the main port and said additional discharge port at each end is spaced from its associated head a distance such that fluid has been captured in said cavity prior to the piston uncovering said discharge port, whereby hydraulic fluid pressure acting on the piston will be reduced during the cushioning of the piston.
 3. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box and agitator means for agitating the concrete discharged into the mold box, the combination of supply means for supplying hydraulic fluid under pressure, agitator means responsive to hydraulic fluid under pressure for agitating concrete in a mold box, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer from a receiving position at the feed hopper to a discharge position at the mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to a position at one end thereof whereby said feed drawer is moved to its dIscharge position, and an additional discharge port in said cylinder adjacent to but spaced from said one end of said cylinder so that the discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover when the latter is moved to said one end of the cylinder, and passage means providing communication between said discharge port and said agitator means so said agitator means will be actuated in timed relation to movement of said piston to said one end of the cylinder.
 4. The combination that is defined in claim 3, wherein hydraulic cushioning means are defined between each end of the piston and the adjacent head of the cylinder, each said cushioning means including a cavity provided between the piston and the adjacent head in which fluid is captured near the termination of the piston stroke and metered to the main port, and said additional discharge port is spaced from its associated head a distance such that fluid is captured in said cavity prior to the piston uncovering said discharge port, whereby hydraulic fluid pressure acting on the piston will be reduced during the cushioning of the piston at said one end.
 5. The combination that is defined in claim 3, wherein variable flow control means are located in said passage means for controlling operation of said agitator means.
 6. The combination that is defined in claim 4, wherein a similar additional discharge port is in said cylinder adjacent to but spaced from the other end of the cylinder, and passage means provide communication between said similar port and the port in its associated head.
 7. In a concrete block making machine having a feed drawer for transferring concrete from a feed hopper to a mold box, the combination of supply means for supplying hydraulic fluid under pressure, and a feed drawer cylinder assembly operably connected to said feed drawer and in communication with said supply means for moving the feed drawer between a receiving position at said feed hopper and a discharge position at said mold box, said cylinder assembly comprising a cylinder having heads at the ends thereof providing ports for ingress and egress of hydraulic fluid, a piston slidable in said cylinder to first and second position at opposite ends thereof and having a piston rod extending through one of said heads for movement of the feed drawer between its receiving and discharge positions in response to movement of the piston between its end positions, an additional discharge port in said cylinder spaced axially from one end of said cylinder so that a discharge port is uncovered to the high pressure side of the piston by passage of the piston thereover immediately prior to the piston reaching the corresponding end of the cylinder, hydraulic motor means for actuation of apparatus associated with the concrete block forming operation, and a passageway in communication with said additional discharge port and said hydraulic motor means for supplying high pressure hydraulic fluid to said hydraulic motor means so that the motor means can actuate said apparatus in timed relation to the location of said piston. 